This invention relates to an apparatus for controlling the movement of a cutting or scribing tool relative to a workpiece, and in particular to an apparatus which facilitates formation in a workpiece of elliptical cuts or markings.
It is often useful, in the decorative as well as useful arts, to be able to make a design following an elliptical path. Items which can benefit from this design can range in size from gravy boats to doors for oversize entryways and beyond.
Conventional apparatus, such as that disclosed in Peot, U.S. Pat. No. 4,306,598, must have the trammel beam arrangement attached to the workpiece in order to function properly. This requirement limits its usefulness. If an oval is to be cut that is smaller than the workpiece support base, a router table must be used. If this base is made smaller to avoid this problem, the maximum size is then limited by the fact that the device becomes unwieldy if the trammel beam is too much longer than the workpiece support base.
Gorman, U.S. Pat. No. 4,281,694, discloses another cutting guide for use with a router. This guide, however, is designed to make a series of regularly-spaced, arcuate or circular cuts, not closed elliptical cuts of any kind.
Neither of these inventions allows for varying the depth of the cut on different passes, or for working around the edge of a workpiece, or for a sufficient range of depth of cut. Neither of these inventions allows both a major and minor radius of zero, which is necessary if the center of a workpiece must be routed out but not cut through, as with a gravy boat of an oval tray having a raised edge. This invention relates to fulfilling these needs and solutions to the problems raised thereby.